package com.panfeng.xcloud.common.core.utils;

import org.apache.commons.codec.binary.Base64;

import javax.crypto.Cipher;
import java.security.*;
import java.security.spec.PKCS8EncodedKeySpec;
import java.security.spec.X509EncodedKeySpec;
import java.util.HashMap;
import java.util.Map;

public class RSACoder {

    public static void getKeyParir() throws Exception{
        Map<String, Key> keyMap = RSACoder.initKey();
        String publicKey = RSACoder.getPublicKey(keyMap);
        String privateKey = RSACoder.getPrivateKey(keyMap);
        System.err.println("公钥: \n\r" + publicKey);
        System.err.println("私钥： \n\r" + privateKey);
    }

    public static void main(String[] args) throws Exception {
        //getKeyParir();
        String publicKey = "MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQCZqKTrHvs0nK8Xo0MPlf8wuuPdrbZ11XP1j+95pS60axwo+DWr0JQpVBJTjEr0zz8SvWe9LiefDguBTwdmjBrS2hvP+dnk+WKtmlXWXpOn8DY9Tzpepdnpk6BMIBjKu3SSWHbOqcimBFj19uPZ8yXO+hx7UUnZZiecqf6FgM1+LwIDAQAB";
        String privateKey = "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";
        System.err.println("公钥加密——私钥解密");
        String inputStr = "buc/user/login/loginToken";
        String encodedInputStr = "hVYUEOh66xRsmvM4hTQJ61rS9IoZz1A3B10cZYMFSZe0+6fx19z2If+Jf3u9mvk8z/T/+n8mfS7MrAYqQ0ieizBlIdVMIeEs1eZNh13gJPsTxksf3W+7WewR1eQe5h5r/KVucNW6BbV6z7hieLxpgDBA8+J9pfkgI4mJJq0h7cc=";
        byte[] decodedData = RSACoder.decryptByPrivateKey(encodedInputStr,privateKey);
        String outputStr = new String(decodedData);
        System.err.println("加密前: " + inputStr + "\n\r" + "解密后: " + outputStr);
    }

    public static final String KEY_ALGORITHM = "RSA";
    public static final String SIGNATURE_ALGORITHM = "MD5withRSA";

    private static final String PUBLIC_KEY = "RSAPublicKey";
    private static final String PRIVATE_KEY = "RSAPrivateKey";

    public static byte[] decryptBASE64(String key) {
        return Base64.decodeBase64(key);
    }

    public static String encryptBASE64(byte[] bytes) {
        return Base64.encodeBase64String(bytes);
    }

    /**
     * 用私钥对信息生成数字签名
     *
     * @param data       加密数据
     * @param privateKey 私钥
     * @return
     * @throws Exception
     */
    public static String sign(byte[] data, String privateKey) throws Exception {
        // 解密由base64编码的私钥
        byte[] keyBytes = decryptBASE64(privateKey);
        // 构造PKCS8EncodedKeySpec对象
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        // KEY_ALGORITHM 指定的加密算法
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        // 取私钥匙对象
        PrivateKey priKey = keyFactory.generatePrivate(pkcs8KeySpec);
        // 用私钥对信息生成数字签名
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initSign(priKey);
        signature.update(data);
        return encryptBASE64(signature.sign());
    }

    /**
     * 校验数字签名
     *
     * @param data      加密数据
     * @param publicKey 公钥
     * @param sign      数字签名
     * @return 校验成功返回true 失败返回false
     * @throws Exception
     */
    public static boolean verify(byte[] data, String publicKey, String sign)
            throws Exception {
        // 解密由base64编码的公钥
        byte[] keyBytes = decryptBASE64(publicKey);
        // 构造X509EncodedKeySpec对象
        X509EncodedKeySpec keySpec = new X509EncodedKeySpec(keyBytes);
        // KEY_ALGORITHM 指定的加密算法
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        // 取公钥匙对象
        PublicKey pubKey = keyFactory.generatePublic(keySpec);
        Signature signature = Signature.getInstance(SIGNATURE_ALGORITHM);
        signature.initVerify(pubKey);
        signature.update(data);
        // 验证签名是否正常
        return signature.verify(decryptBASE64(sign));
    }

    public static byte[] decryptByPrivateKey(byte[] data, String key) throws Exception{
        // 对密钥解密
        byte[] keyBytes = decryptBASE64(key);
        // 取得私钥
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);
        // 对数据解密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, privateKey);
        return cipher.doFinal(data);
    }

    /**
     * 解密<br>
     * 用私钥解密
     *
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPrivateKey(String data, String key)
            throws Exception {
        return decryptByPrivateKey(decryptBASE64(data),key);
    }

    /**
     * 解密<br>
     * 用公钥解密
     *
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] decryptByPublicKey(byte[] data, String key)
            throws Exception {
        // 对密钥解密
        byte[] keyBytes = decryptBASE64(key);
        // 取得公钥
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicKey = keyFactory.generatePublic(x509KeySpec);
        // 对数据解密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.DECRYPT_MODE, publicKey);
        return cipher.doFinal(data);
    }

    /**
     * 加密<br>
     * 用公钥加密
     *
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPublicKey(String data, String key)
            throws Exception {
        // 对公钥解密
        byte[] keyBytes = decryptBASE64(key);
        // 取得公钥
        X509EncodedKeySpec x509KeySpec = new X509EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key publicKey = keyFactory.generatePublic(x509KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, publicKey);
        return cipher.doFinal(data.getBytes());
    }

    /**
     * 加密<br>
     * 用私钥加密
     *
     * @param data
     * @param key
     * @return
     * @throws Exception
     */
    public static byte[] encryptByPrivateKey(byte[] data, String key)
            throws Exception {
        // 对密钥解密
        byte[] keyBytes = decryptBASE64(key);
        // 取得私钥
        PKCS8EncodedKeySpec pkcs8KeySpec = new PKCS8EncodedKeySpec(keyBytes);
        KeyFactory keyFactory = KeyFactory.getInstance(KEY_ALGORITHM);
        Key privateKey = keyFactory.generatePrivate(pkcs8KeySpec);
        // 对数据加密
        Cipher cipher = Cipher.getInstance(keyFactory.getAlgorithm());
        cipher.init(Cipher.ENCRYPT_MODE, privateKey);
        return cipher.doFinal(data);
    }

    /**
     * 取得私钥
     *
     * @param keyMap
     * @return
     * @throws Exception
     */
    public static String getPrivateKey(Map<String, Key> keyMap)
            throws Exception {
        Key key = (Key) keyMap.get(PRIVATE_KEY);
        return encryptBASE64(key.getEncoded());
    }

    /**
     * 取得公钥
     *
     * @param keyMap
     * @return
     * @throws Exception
     */
    public static String getPublicKey(Map<String, Key> keyMap)
            throws Exception {
        Key key = keyMap.get(PUBLIC_KEY);
        return encryptBASE64(key.getEncoded());
    }

    /**
     * 初始化密钥
     *
     * @return
     * @throws Exception
     */
    public static Map<String, Key> initKey() throws Exception {
        KeyPairGenerator keyPairGen = KeyPairGenerator
                .getInstance(KEY_ALGORITHM);
        keyPairGen.initialize(1024);
        KeyPair keyPair = keyPairGen.generateKeyPair();
        Map<String, Key> keyMap = new HashMap(2);
        keyMap.put(PUBLIC_KEY, keyPair.getPublic());// 公钥
        keyMap.put(PRIVATE_KEY, keyPair.getPrivate());// 私钥
        return keyMap;
    }
}